861bhp Subaru Impreza Time Attack Build: UK's Ultimate Homebuilt Track Machine

The Ultimate Homebuilt Subaru Impreza Time Attack Machine

When it comes to modified Subarus in the UK, Rich White's Impreza time attack build represents something truly extraordinary. This isn't merely a road car with cosmetic enhancements - it's a purpose-built circuit weapon developing 861bhp, featuring full carbon bodywork, a sequential gearbox and aerodynamic capabilities that dwarf typical track toys. What makes this build particularly remarkable is that Rich constructed most of it himself in a home garage using basic equipment.

Seventeen Years in the Making: From Bare Shell to Circuit Dominator

Rich White's relationship with this particular Impreza began back in 2008 when he acquired it as a bare shell. For seventeen years, he has been meticulously developing what he describes as a "super crazy" circuit car without compromises. The inspiration came from his previous experience with a Nissan Pulsar track car, which suffered from platform limitations like weight distribution issues. The Subaru platform offered the perfect foundation for his ultimate time attack ambitions.

Engineering Excellence: Carbon Construction and Aerodynamics

WRC-Inspired Carbon Bodywork

The car features S5 WRC-style carbon panels sourced from Aerosim in California, including carbon doors and wider outer bodywork. This isn't merely for appearance - behind the carbon lies extensively modified steel structure with removed arches and tubbed front and rear sections to accommodate the extreme track hardware.

Professional-Level Home Fabrication

While professional assistance was sought for painting, wiring and the certified roll cage, Rich personally handled the bulk of fabrication work. Using a basic MIG welder, he created the arch tubs with the car inverted on a rotisserie and installed competition-spec air jacks for quick pit stops.

Advanced Aerodynamic Package

The aerodynamic components include a front splitter and diffuser from a Greek time attack car, heavily modified to suit this build. The rear wing is a DJ Race Cars item mounted on a custom T45 support structure fabricated by Rich himself. Underneath, a full carbon flat floor of his own creation completes the package, with added cooling ducts to address overheating issues caused by reduced airflow.

Competition-Grade Chassis and Suspension

The chassis modifications are equally impressive, retaining standard Subaru engine and gearbox positions but featuring tubular subframes front and rear. The front uses a Moresport subframe from Canada while the rear incorporates a Prodrive WRC unit, both aimed at optimising the platform and eliminating understeer.

Suspension consists of custom-shortened AST four-way dampers (worth approximately £8,000 new) acquired secondhand, while braking is handled by water-cooled AP eight-pot calipers from a Skoda Fabia WRC car, using four pads per caliper. This setup perfectly complements a car that produces over 700bhp on pump fuel while weighing little more than a modern hot hatch.

Boxer Power: The 2.35-Litre Heart

At the core of this build lies what Rich describes as the "holy grail" of Subaru four-cylinder engines. Based on an EJ22 closed deck block sourced from the US and expanded to 2.35 litres, it features Ric Wood CNC heads, a billet Arrow crank and CP pistons. The long motor was assembled by Paul Finch, an ex-Mercedes F1 engine builder renowned in Subaru circles.

Forced induction comes from a BorgWarner EFR 8474 turbocharger, chosen after downsizing from a larger unit to maintain power while improving response. The engine produces boost from around 3,500rpm and revs to 8,500rpm, utilizing fresh-air anti-lag via a Turbosmart valve and Inconel exhaust manifold.

The headline figures are staggering: 861bhp on Sunoco 118 race fuel and approximately 700+bhp on Shell V-Power pump fuel. Performance includes a 9.4-second quarter-mile at 147mph despite suboptimal launch conditions, suggesting even greater potential exists. With a weight of 1,160kg including aero and half a tank of fuel (excluding driver), the power-to-weight ratio is nothing short of extraordinary.

Drivetrain and Interior: Pure Competition Spec

The transmission features a Samsonas six-speed sequential gearbox paired with an Xtreme triple-plate clutch, Driveshaft Shop front and rear shafts, and a custom-length carbon prop shaft. Power distribution is handled by a Cusco RS 1.5-way differential described as clunky and aggressive - perfectly suited to this focused build.

Inside, the car is pure race specification with a Tilton pedal box, dry sump tank, air jack controls, Syvecs S8 ECU, MoTeC PDM, MoTeC dash and Race Technology electronics all communicating via CAN bus. A wireless keypad and paddle-shift setup is in development, though the gearbox actuator requires fitting before full operation. Unsurprisingly, there's no stereo - when you have 861bhp and sequential shifting, entertainment comes from the driving experience itself.

Competition Readiness and Future Developments

Rich continues to develop the car with plans for a Bosch M5 Clubsport ABS upgrade, additional sensors and enhanced data logging to support calibration and driver development. GR Performance, who handle the mapping, require more information on wheel speeds, brake pressure and consistency to optimise the setup further.

The long-term ambition remains proper Time Attack competition in the Pro Extreme class, which Time Attack UK describes as the category "where almost anything goes" for heavily modified cars. As a self-described Time Attack newcomer, Rich plans a one-off event initially, with Brands Hatch high on his target list.

The Ultimate Homebuilt Achievement

What makes this Subaru Impreza truly special isn't just the staggering performance figures but the deeply personal seventeen-year journey of development and refinement. This represents the pinnacle of home fabrication and long-term commitment to a single project, resulting in a machine capable of competing with professional-level time attack machinery. For UK enthusiasts wondering what's possible with dedication and skill, this Impreza provides the definitive answer.